Sucker-rod guard



Patented Apr. 11, 1939 UNITED STATES PATENT OFFICE 2.153.781 SUCKEB-RODGUARD David R. Anderson, Dallas, Tex, assignor to The F. GoodrichCompany, New ork, N. Y., a corporation oi New York Application July 16,1937, Serial No. 154,015

1 Claim. 808-4) This invention relates to pumping apparatus, at about300 F., cut to length, and chamiered and among its objects to providesucker-rod at both ends. guards which will prevent the rod from con-Rubber sucker-rod guards have been made with tacting the well casing,and to provide a guard their inside diameter smaller than the outside 5which will contain no metal or other material diameter of the rod overwhich it was to be which would be injurious to pumping equipment iorced.These guards were very hard to apply, should the guard break and becomeengaged and they soon loosened due to the softening eftherein. feet orthe oil upon the rubber. I make the inon the downward stroke. necessary,therei'ore, to place guards every few yards along the rod and to takespecial care to 15 provide protection in crooked parts 01' the well inorder to avoid abrasion between the rod and the casing. Many typesotguards have been proaway and in section, ed on a sucker-rod, and Fig.2 shows a section on the line 2-2.

Referring to the drawing, the guard ll side diameter of the guard aboutthe same size as the outside diameter 01 the rod so that the guard gripsthe rod loosely and is easily applied. The oil extracts some of theplasticizer from the polyvinyl chloride causing it to shrink and gripthe rod very tightly. Thus, my guards tighten on the rod instead 01'loosening, and their length or service is many times that of the rubberguards.

Though I prefer to use tricresyl phosphate as the plasticizer for thepolyvinyl chloride, other well known materials such as dibutylphthalate, o butyl phthalyl butyl glycollate, o-nitro diphenyi ether;etc., may be used with satisfactory results.

Other substances besides the plasticizer may be added to the polyvinylchloride to vary the properties of the finished product. Theseadditional substances include carbon black, zinc oxide, clay, fibrousmaterials such as asbestos and wood flour, and other pigments andfillers commonly used in the rubber and plastics industries.

While I have herein disclosed specific detailso 01 my invention, I donot intend to limit myself wholly thereto, for materials havingequivalent properties may be substituted and the proportions ofmaterials used may be changed without exceeding the spirit and scope oithe appended claim.

I claim:

A sucker-rod guard'for oil wells consisting oi a ring made of acomposition comprising a gamma polyvinyl chloride and plasticizerslightly soluble in oil, whereby said ring is caused to grip theextracts the plasticizer shrink.

sucker-rodwhentheoil andcausectheringto DAVID R. ANDERQON. 5

